Allstar Performance Heated Tire Groovers add extra traction in minutes. Tapered, razor sharp blade groove fast and easy. To operate, insert a blade into the groover, set blade height with a tire depth gauge, and set the power level. Place the cutting edge against the tire surface and apply pressure to activate rocker switch for instant heat. Includes 4/32", 6/32", 8/32", and 10/32" flat blades.